Load capacity testing device



Jan. l, 1946. L. MCHARG 2,392,096

/ LOAD CAPACITY TESTING DEVICE Filed oct, 2s, 1944 JNVENTOR. jb'- [as'e /f/c Haig' t BY 5 fwd 2% J M f mmm/aya Patented Jan. 1, 1946 vUNITED STATE S PATENT OFFICE vLGA!) TESTING 'DEVICE Leslie McHam, Huntington, N. Y.

Application Gctober 23, 1944, fSe-ial No. 559,902

4(Cl. .7S-141) 6 Slaims.

The invention relates toa Xload capacity testing device or scale `for determining whether or not a structure comes within the maximum capacity of the -lcad which the Istructure is intended to carry -or withstand. The testing device is particularly applicable to Atesting the strength of booms such as are found lon ships, derricks, shovels and the like. The testing device is attached to the structure the strength ,of vwhich is 4to fbe tested and also anchored to a xed structure whereupon -a load is applied to the structure which is in excess of -the load Whichthe structure is intended to carry. In testing the boom, the device is attached to the lifting cables or block operating `from the boom. The load applied is measured or `balanced by the 'testing device so that the device is aload measuring scale.

It iis an obect of the invention 'to construct a new and novel load testing device.

Another object is to construct a load testing device for very heavy loads which is effective and also simple in its construction and inexpenm've to build.

Another object is to construct a load testing device which divides lthe load so that each scale element measures or balances a portion only of the vfull load applied.

Another object is `to construct a load testing device :using pairs of lever arms in which one arm of the pair largely counter-balances the Weight of the other arm of the pair.

A still further object is to construct a load testing device having Aa new and novel frame.

Other objects of the inventionwill be `more Aapparent from the following -description taken in connection -with the accompanying drawing which ilustrates ya preferred embodiment ythereof in which:

Figure 1 'is a top elevation-of the testing device in section.

Figure 2 is a longitudinal section through the testing device taken on line 2---2'of `Figure 1.

Figure 3 is a longitudinal section through the testing device ltaken on line 3-3 Vof Figure' '1.

' 'Figure 4 is across section through the' device taken on line '4--4 of 'Figure 2. The testing r'device Iutilizes a 'plurality lof bal- Yancing means connected together lwith :a 'load .applying connection .in order to divide the load. 'In the construction Lparticularly illustrated a pair l, vof balancing means lis shown which divides Ythe load in half. It is clear that additional balancing mea-ns would further divide the load applied to .the Vtesting device.

withstanding the heavy Alforce or load applied thereto when testinga structure. The trame may be of a-ny suitable construction, however that illustra-ted is simple and effective rand inciude's a pair of channel irons or 'beams vl'l1 and 1'2 which are secured in spaced relation in any suitable fashion such as by a top yplate i3 and a 'bottom plate l 4 secu-red to the flange of the channel irons at the top and bottom respectively of the vframe such as by bolts. The frame also .carries anchoring means which is shown as yformed by brackets I5 secured as by welding to each channel iron :and proecting through the bottom plate .and below the frame, The brackets have a hole .'IE to `:receive a pin which is adapted 'to receive a shackle or other structure for anchoring 'the iframe =.t0 some fixed structure. vFor testing the 'boom fof a ship :the frame Aoi the testing device may be :anchoredzto any part of the ships structure.

A pair of balancing means is .shown which includes -a 'f1-rst 4pair of arms I'B and I8 extending 'in 'opposite directions vfrom the center oi the frame and `are vpivotally supported at their adjacent ends upon 1Jthe frame. Preferably a pivot 211 and 2i is provided for v`the respective arms and the arms are mounted npon self-:centering roller hearings. 'The pivots 20 and 121 are mounted upon the frame or chan-nel irons and the brackets :I5 may extend along the faceor web Vof the Icha-nnel and also serve as reinforcing plates for the pivots. Means are utilized to connect the load with each 'balancing means so that the load is divided. Each of the arms at their adjacent ends have means for anchoring the same to the cable or hook of the boom or structure to be tested. Any suitable connection may be used, however, the simple structure illustrated is preferred. This includes a metal strap 22 bent in the form of yan inverted U and having each end or leg 23 -bent Varound the fend of an arm and secured thereto, such as by welding. "The upper .U portionr projects through ithe top plate I3 lof the frame and is adapted to receive a hook or `other means `carried by the boom to be tested. The outer end of each arm carried a load ltransfer means 2li which rmay be a ball or a knife edge.

A .second `pair oi arms including an arm 28 .and an ar-xn 11B-iis carried by the frame in any desitedl location thereon. in the illustrated construction, .one arm 'is located between the ilanges of each channel iron on the opposite side of the web from .the iirst arms i8 and I9. Each arm 28 and 29 is carried upon a pivot shaft A39 and .A3-l respectively each mounted in 4suitable bearings at The testing device includes a frame 4capable of 55 the end of the frame. Each of the arms 28 and '2,9

arm 28 or 29.

' lever ratio between the two arms.

extends the full length or substantially the full length of the frame or the combined length of the first pair of arms. Each of the second pair of arms may have a counter-weight 34 for counter-balancing the Weight of the arm which counter-weight may be carried on an extension 32 which projects beyond the end of the frame. A balancing Weight 33 is slidably mounted upon each of the ar1ns28 and 29. The arms 28 and 29 may .be entirely, or partiallyfof aluminum as illustratedjin order Vto lighten the weight of the arm and hence lighten the counter-weight.

' A connection is made between the outer end of each rst arm I8 and I9 or the load transferring means 24 thereof and its respective second arm, that illustrated including the respective pivot shaft 30 or 3l pivotally mounted in the frame and fastened such as by the key 3l to its respective sion or platform 38 which is engaged, at va point removed about one inch,V for example, from the axis of the shaft, by the load transfer means 24 carried upon the end of each arm I8 and I9. There is thereforea substantial increase in the The load transfer means 24 engages-the platform upon the opposite side of the pivot axis from which its respective'second arm'28 or 29 extends. With this arrangement the second arm is counterbalanced largely bythe weight of the first arm so that a minimum weight 33 is needed to counterbalance the system of levers.

' Each system of levers disclosed provides a maximum leverage ratio of approximately 1000 to 1 and with the load applied being divided between the pair of leverages or balancing means, the slidable weights 33 will balance a load applied to the load applying means or strap 22 of as large as 55,000 pounds. It is clear that the testing device may have a range greater or less than that used as 'an example merely by proper proportioning of parts. In the preferred construction each balancing means includes a pair of levers namely the first arm i8 and its second arm 28, and the first arm I9 and its second arm 29. This system of pairs of levers is needed for heavy loads in order Y to obtain a high leverage ratio. If a high ratio is not needed a plurality or a pair of balancing means may be used comprising single levers alone with the load being divided between each balancing means.

. A closing plate 4| may be carried upon each side of the frame upon hinges 42 in order to enclose each side face of the frame and enclose the second arms of the testing device. End plates 43 may also be secured to the ends of the frame by brackets 44 in order to completely enclose the mechanism.

The dividing of the load applied to the testing device not only reduces the force which each set of levers isV to balance but also balances -the weight of the device so that it remains horizontal or in substantially horizontal'position when in use. Since the frame and the parts are necessarily-heavy, it ismuch easierto handle if it balances horizontally when the boom lines are pulled .and the load begins to be applied to the tester. Usually the balancing weights are fixed upon the bar by a set screw at a position representing a twenty-five percent overload :on the boom and the load is increased until the two arms lift to show that the full overload stress is carried by the boom. l

- The invention is presented to ll a need for improvements in a load capacity testing device. VIt

The pivot shaft carries an exten-` is understood that various modifications in structure, as well as changes in mode of operation, assembly, and manner of use, may and often do occur to those* skilled in the art, especially after beneting from the teachings of an invention. Hence, it will be understood that this disclosure is illustrative of preferred means of embodying the invention in useful form by explaining the construction, operation and advantages thereof.

What isrclaimed is:

1. A testing device for testing the strength of structures such as booms comprising a frame,

. means carried by the frame to anchor the same to some other structure, a pair of arms with the adjacent end of each arm being pivotally mounted upon the frame and the remote end being free, means connected to the adjacent end of each arm to apply a load simultaneously thereto, a second pair of arms extending substantially the combined length of both arms of the first pair of arms, one arm of the second-pair being pivotally mounted on the frame adjacent the free end of one arm of the first pair and the other arm'of the second pair being pivotally mounted on the frame adjacent the free end of the other arm of the first pair, and means connecting the free end of each arm of the rst pair to its respective arm of the second pair and adjacent its pivot to transfer the force thereof to the second arm.

2. A testing device for testing the strength of structures such as booms comprising a frame, means carried by the frame to anchor the same to other structure, a pair of arms .with the adjacent end of each arm being pivotally mounted to the frame and the remote end being free, means connected to the adjacent end of Veach arm t0 apply a load simultaneously thereto, a

,. of arms, one arm of the second pair being pivotally mounted on the frame adjacent the Vfreel end of one arm of the first pair and the other arm of the second pair being pivotally mounted on the frame adjacent the free end of the other arm of the first pair, means connecting the free end of each arm of the iirst-pair to its respective arm of the second pair to transfer the force thereof to the second arm, and a balancing weight movable along eachlarm of the second pair of arms.

3. A testing device for ltesting the strength of structures such as booms comprising a frame, means carried by the frame to anchor vthe-same to some other structure, a pair of arms with the adjacent end of each arm being pivotally mounted to the frame and the remote end being free, a U shaped strap having one end connected to the adjacent end of one-arm aforesaid and the other end connected to the adjacent end of the other arm to apply a load simultaneously thereto, a second pair of arms extending substantially the combined length of 'both arms ofthe rst pair of arms, one arm of the second pair being pivotally mounted on' the frame adjacent the free end of-one arm of the first pair and the other arm of the second pair being pivotally mounted on the frame adjacent `the free end 0f the other arm of the first pair, means connecting the free end of each arm of the first pair of to its respective arm of the second pair to transfer the forcef thereof to the second arm, and a balancing weight movable along each arm of Vthe second pair.

4. A device for testing the strength of structures such as` booms comprising a frame formed from a, pair of channel irons secured together in spaced relation with their flanges extending outwardly, means carried by the frame to anchor the same to some other structure, a pair of arms extending away from each other and positioned between the channel irons, the adjacent end of each arm being pivotally mounted upon the frame` and the remote end being free, means connected to the adjacent end of each arm to apply a load thereto, a second pair of arms each arm extending substantially the combined length of both arms of the first pair of arms, one arm of the second pair being pivotally mounted on each channel iron of the frame between the flanges thereof and adjacent the free end of each arm of the first pair, means connecting the free end of each arm ofthe first pair to its respective arm of the second pair to transfer the force thereof to the second arm, and' a balancing weight movable along each arm of the second pair.

5. A device for testing the strength of structures such as booms comprising a frame, means carried by the frame to anchor the same to some other structure, a pair of armsextending away from each other and the adjacent end of each arm being pivotally mounted upon the frame and the remote end being free, means connected to the adjacent end of each arm to apply a load thereto, a second pair of arms each arm extending substantially the combined length or both arms of the first pair of arms, a pivot mounted in the frame adjacent the free end of each arm of the rst pair and secured to its respective arm of the second pair, a platform carried by the pivot, means carried by the free end of each arm of the rst pair and engaging its respective pivot platform to transfer the force thereof to the second arm, and a balancing weight movable along each arm of the second pair.

6. A device for testing the strength of structures such as booms comprising a frame, means carried by the frame to anchor the same to some other structure, a pair of arms extending away from each other and the adjacent end of each arm being pivotally mounted upon the frame and the remote end being free, means connected to the adjacent end of each arm to apply a load thereto, a second pair of arms each arm extending substantially the combined length of both arms of the rst pair of arms, a pivot mounted in the frame adjacent the free end of each arm of the first pair and secured to its respective arm of the second pair of arms, a platform carried by the pivot projecting in a direction opposite from the direction in which the second arm projects, means carried by the free end of each arm of the first pair engaging its respective pivot platform to transfer the force thereof to the second arm, and a balancing weight movable along each arm of the second pair.

LESLIE MCHARG. 

